Most chewing gum compositions, including bubble gums, contain a generally water-insoluble gum base, water-soluble sweeteners that are either natural or artificial, and a flavoring that may be added in a variety of forms. Also, the gum may contain various additives such as plasticizers, softeners and bulking agents to improve consistency and to generally enhance the chewing experience.
A commonly noted deficiency in chewing gums has been the relatively rapid exhaustion of the flavor and sweetness sensation during chewing. This loss frequently occurs within the first 3 to 5 minutes of chewing.
The same problem is observed in the instance where the gum products are stored for a period of time between manufacture and consumption. The flavors appear to have limited shelf stability and, in some cases, are observed to diminish to an unacceptably low level within one month after storage.
Recently, it has become desirable to develop chewing gums and bubble gums having extended flavor and/or sweetener release.
U.S. Pat. No. 3,920,849 to Marmo et al addresses the concept of extended flavor release and offers a full discussion of the prior art on this subject. The patent directs itself to the preparation of separate flavor components identified as "fixed" (encapsulated) and "unfixed", which are mixed with a suspension agent prior to their addition to a chewing gum base. The patentees contend that this method of preparation and addition to the chewing gum offers improved flavor intensity and uniform flavor transmission. The patentees specifically employ a non-confined hydrophobic flavor oil and a "fixed" hydrolytically releasable flavor oil in combination with a solid suspending agent, as their flavor system. The preparation of the flavors is such that the resulting flavor system is added simultaneously to the gum base.
In similar fashion, U.S. Pat. No. 4,001,438 also to Marmo et al discloses a flavor composition utilizing a non-confined flavor oil in combination with a flavor oil physically entrapped within solid particles, and a suspending agent combined therewith. All of these ingredients are premixed and thereafter simultaneously added to the product to be flavored. It is significant that the flavor system of this patent is predicated upon an intimate admixture between the non-confined flavor oil and the entrapped flavor oil.
In contrast to the Marmo et al. technique, U.S. Pat. No. 3,826,847 to Ogawa et al. relates to encapsulation of flavoring oils with polyvinyl acetates, that is high molecular weight material. The encapsulated oil is thereafter incorporated into a chewing gum base. Ogawa et al purport to achieve sequential flavor delivery by the modulation of the coating applied to the respective flavor particles.
While the foregoing patents have been directed to flavor release, the art has concurrently developed to achieve prolonged sweetness release. U.S. Pat. No. 4,217,368 to Witzel is representative of one means utilized to delay sweetener release. This patented system involves using two phases, a watersoluble phase consisting essentially of softener and a first sweetener in particulate form and a relatively water-insoluble phase consisting of a plurality of separate and distinct masses suspended in the water-soluble phase, each of said masses comprising gum base and particles of a second sweetener enveloped in the gum base. The prior art has continued to explore encapsulation of sweeteners that will release over extended periods.